[scribus] Making a large poster out of smaller sheets of paper

[Salomea]

I have a large poster. But I only have access to small A4 printers.
First I have gone by the way of Gimp. Using the guillotine to break a
large image into smaller pieces. Quite a pain. Than I have discovered
PosteRazor. Compared with Gimp, this is a walk in the park. In the end I
get a PDF with the pages. But I still have to guess the page position
from the printing order. I have no guides for cutting and none for
sticking the pages together. It is faster, yet still a large part of the
work done blindly. The only help is that small mistakes are harder to
spot on larger posters.

Now I have a new idea. Scribus has everything I need. Guides. And marks.
But how do I feed Scribus a large image and get the multi-page document
that has all the markers to assemble the final poster on the given
support media?

Cheers!